Drones or UAVs can be classified in many different ways based on size, range, weight, purpose, and power source, and etc. The most important classification of surveying drones, however, is rotary wing and fixed wing. Although both widely used in photogrammetric surveys, these two types drones have different advantages and drawbacks. According to PrecisionHawk, the fixed wing platform follows the usual airplane design and flies a preprogrammed flight path (think PrecisionHawk and Sensefly). On the other hand, the rotary type, which uses a multi-component propeller system, can move in several directions, think Aeryon Labs and 3D Robotics. Fixed wing UAVs are able to calculate flight plans and capture consistent data across large areas, while rotary UAVs can hover in a single location for some time and be used for thorough inspections.
Our choice of drones are two consumer grade low-cost quadcopters:
a. DJI Phantom 3 pro (circa $800)
b. DJI Phantom 4 pro (circa $1800)
To learn more about other options, please see the following information we copied from DroneZon https://www.dronezon.com/learn-about-drones-quadcopters/introduction-to-uav-photogrammetry-and-lidar-mapping-basics/
You may use an iPad, iPhone, tablet, or a DJI Phantom 4 high luminance display as your viewing device.
DJI Phantom 4 Remote Controller with Built-in Screen
Read more at: http://www.gizbot.com/gadgets/news/dji-phantom-4-advanced-launched-with-high-end-camera-intelligent-features/slider-pf72582-039960.html
Using an iPad as a viewing device (also note the sunhood)
a .extra batteries (one battery can last 25-28 minutes of flight time under ideal conditions)
b. extra charger and power cord (recommend one pair for every two batteries for quick recharging)
c. bigger micro SD cards
d. Controller Monitor Hoods (sun hoods)
e. hard cases
Ground control point (GCP) markers
It is necessary to have some GCPs to achieve accurate results if you are not using professional mapping drones, such as senseFly eBee. To be able to easily identify these GCPs on your aerial photos, you will need to use some markers. If funding permitted, a good option is the smart ground control points, such as the AeroPoints by Propeller Aero (10 for $6000, can be used to obtain accurate results for an area of 120ha). These smart ground control points only only help you mark the GCPS, but also automatically record the accurate location of the GCPs, which will save you a lot of time and energy measuring them with professional surveying equipment. The other low cost option is to purchase some fabric markers or make your own marker with ceramic tiles or other materials. The most important thing is that they all need to have a clearly marked center point. If possible, mark the targets with numbers for easier identification. In terms of the total number of photo targets needed for a project, there is no consensus among researchers as it varies for every project. The usually recommended number is 8 to10 for an area covered by one flight (if using DJI drones), but it is always a good idea to have some extra for final quality check. Sometimes you can take advantage of some "natural" points and use them a supplement to your GCP markers.
Fabric GCP marker
Painted GCP marker
Necessary to accurately map the GCPs. The most commonly used surveying equipment include total station and RTK. To use these equipment, usually you will need to have at least one or two known points.
for checking the quality of photos in the field and backing up data